1. Field of Invention
This invention relates generally to processing cattle or other livestock animals during the slaughter process and, more particularly, to washing/rinsing the hide of an animal and removing water from the hide.
2. Background Art
In a meat processing plant, an animal's exterior hide is usually cleaned before the hide is removed, because it is typical for contaminants present on the exterior of the hide to be transferred to the meat of the animal during the hide removal process. As an alternative, the hide of the cattle can simply be wetted to remove loose contaminants or particles from the hide. This transfer can typically occur when knife cuts are made into the hide. Cleaning or wetting animals in meat processing plants can be challenging, but it is necessary because animals typically arrive at a meat processing plant with at least some contamination on their exterior. Contamination can often be worst around the animal's anal region, but can exist anywhere on the hide. Cattle and other livestock have been traditionally washed or wetted at abattoirs/slaughter houses, prior to slaughter, by either hosing them down with a high pressure water hose, or by allowing the animals, particularly so in the case of sheep, to pass through a swim bath. Using a high pressure spray separately or in combination with a bath may result in the spread of contamination present on a hide or the swim wash/wetting used on its own may also provide a breeding ground for contamination. The animals may superficially appear to be clean, but in fact may pick up contamination from the spray off another animal or from the bath, which may in turn contaminate the meat.
Animals when processed are typically suspended from their hind legs, thus contamination from the anal regions can easily be spread from there to other parts of the animal's exterior. Therefore, animals are typically cleaned or wetted while they are alive and on their own feet. The cleaning often involves baths or spray washes and it is usually necessary to allow the animals to at least partially dry before further processing.
However, while they are still alive, the animals can still defecate and can contaminate one another, and since their bodies are warm any residual water or moisture on the animal's body can simply help to stimulate the re-growth of large populations of microbial contaminants. The methods typically employed involved the use of manual steps. If water is used in the cleaning or wetting operation, it is difficult for a single operator to apply sufficient water and to control where the water goes. Water that is allowed to drain from one region of the hide to another can result in contamination to other parts of the animal's hide and therefore this draining action must be minimized. Also, water that sprays off an animal as it is being cleaned can contaminate other animals on the chain.
Yet another problem with water draining from the hide of cattle is the water can also contaminate and/or reduce the quality of the blood plasma rendered from the slaughtered cattle by dripping and intermingling with the plasma such that the plasma is no longer fit for subsequent use. If water is still dripping during the Plasma Saving section of the slaughter process, water can inadvertently drip into the bleed pan, thereby affecting the blood plasma by rupturing the red blood cells in the raw blood thereby not allowing for a quality plasma to be produced. Previous efforts for removing excess water, thereby reducing water run off, have not been effective enough to reduce the water drainage by a significant enough level such that a quality plasma can be produced. Previous solutions have been to wet the cattle after the Plasma Saving section or to allow enough drip time to occur before the cattle reach the Plasma Saving section. This methodology is a disruption to the natural flow of the conveyance line and could require significant modifications to the kill floor layout where there is not enough drip time to allow for excess water run off. In facilities where the animals are bled before the cattle wetter, there is often a lower blood yield and higher protein loadings sent to the wastewater treatment facility. After the initial bleed time, there is still a significant amount of blood that will drip from the wound. This blood has value if it can be successfully processed and will result in increased cost if it is sent to the wastewater treatment facility.
The spread of contaminants into the air can also result when spraying an already wet animal resulting in the spread of contaminants throughout the immediate area. Therefore, it can be necessary to contain the cleaning or wetting within an isolated compartment to prevent the spread of contaminants to other parts of the production line or between animals. It is crucial that contaminants are not allowed to spread from one animal to another. Various drying techniques have been attempted, which follow quickly behind any water washing or wetting activities. The effectiveness of the drying technique can effect the spread of contaminants. Vacuum nozzles as well as blower nozzles have been attempted.
It is desirable to clean or wet the pelt in such a way that it is not damaged, and it is also particularly desirable that dirt is removed from the pelt in at least those areas where incisions will be made by the slaughter men, in order to minimize the risk of contamination of the meat either by cutting through a dirty pelt, or when the carcass is being opened up, a dirty portion of the pelt falling back on to the meat, giving rise to the possibility of contamination if dirt or bacteria in contact with the open carcass.